1. Field of the Invention
The present invention relates to a disc drive apparatus that rotates a disc-shaped recording medium at a constant velocity, for example, a disc drive apparatus that can print visible information such as characters and designs by ejecting ink droplets onto a label surface of a disc-shaped recording medium rotated at a constant velocity.
2. Description of the Related Art
One example of an existing disc drive apparatus is disclosed in Japanese Unexamined Patent Application Publication No. 2001-291235. The publication relates to an optical disc drive apparatus having a function for recording data on a data recording surface of an optical disc and a function for carrying out label printing on a label surface of the optical disc. The optical disc printing apparatus disclosed by the publication includes a disc driving mechanism for supporting and axially rotating the optical disc, a data head for recording and reproducing data on the optical disc that is provided facing the data recording surface of the optical disc supported by the disc driving mechanism. The optical disc printing apparatus further includes a data head driving mechanism for moving the data head back and forth in the radial direction of the optical disc supported by the disc driving mechanism, a label printing head provided facing the label surface of the optical disc supported by the disc driving mechanism, and a print head driving mechanism for moving the label printing head back and forth in the radial direction of the optical disc supported by the disc driving mechanism. In the optical disc printing apparatus, the data head and the label printing head are moved while rotating the optical disc to record or reproduce data on the data recording surface and print on the label surface.
The optical disc drive apparatus disclosed by Japanese Unexamined Patent Application Publication No. 2001-291235 with the construction described above has a stated effect of realizing an optical disc drive apparatus that uses a label printing head with a low cost construction where the label printing head is free to move in only a single dimension, that is, back and forth in the radial direction of the optical disc, and uses the rotation of the optical disc on which data is being recorded or reproduced so as to be able to print on the entire label surface, i.e., a two-dimensional surface (see Paragraph [0008]).
Another example of an existing disc drive apparatus of this type is disclosed by Japanese Unexamined Patent Application Publication No. 2005-346778. The publication relates to a disc drive apparatus that correctly determines a recording position when recording (forming) designs or characters (images) on the label surface. The disc drive apparatus disclosed by the publication records and reproduces information on an information surface of a recording disc having a label surface provided with a pit sequence, where pits for guiding are provided with a predetermined pitch, and records or forms images or characters on the label surface. The disc drive apparatus includes a system control circuit that controls the various components of the disc drive apparatus, and an optical pickup that emits laser light to record or reproduce information on the information surface of the recording disc and/or to form images and characters on the label surface. The disc drive apparatus further includes a focus servo circuit that carries out focus control according to instructions from the system control circuit to drive a focus actuator of the optical pickup based on the focus error signal, and a tracking servo circuit that carries out tracking control according to instructions from the system control circuit to drive a tracking actuator of the optical pickup based on a tracking error signal when recording or reproducing data and carries out label surface print tracking control based on the disposed pits when printing on the label surface.
The disc drive apparatus disclosed by Patent Document 2 with the construction described above has a stated effect that when images and characters are recorded (formed) on the label surface of the recording disc, a base position of the recording disc is detected from the arrangement of pits to correctly determine a freely chosen recording starting position (see Paragraph [0033]).
However, for the optical disc drive apparatus disclosed by Japanese Unexamined Patent Application Publication No. 2005-346778, since the rotational velocity of the optical disc varies according to the employs a function to carry out an ink ejection timing control processing. In the ink ejection timing control processing, the ejection timing of the label printing head is corrected before the ink ejection processing is carried out. That is, in the ink ejection timing control processing, first an ejection timing correction processing is carried out to detect a base angle (i.e., polar axis) for rotation of the optical disc, and then the ejection timing correction processing is carried out again to determine whether the ink ejection start angle has been reached. Once the ink ejection start angle is reached, the ejection timing correction processing is carried out again to correct the ejection timing and then the ink ejection processing is carried out. In this manner, if the ejection timing of ink is synchronized with the rotation of the optical disc that is a constant linear velocity, it may be necessary to frequently correct the ejection timing. As a result, control over ejection timing has been complicated.
The disc drive apparatus disclosed by Japanese Unexamined Patent Application Publication No. 2005-346778 is constructed so that when images and characters are printed on the label surface, CAV (constant angular velocity) control is carried out over a spindle motor so that FG pulses generated by a frequency generator (FG) have a constant frequency. Thus it is desirable to provide a frequency generator (FG) that is directly coupled to the rotational shaft of the spindle motor, which leads to an increase in the apparatus cost.
In addition, the disc drive apparatus according to this publication is constructed so that position information is obtained for the recording disc that is being rotationally driven by detecting the pit sequence on the recording disc. Accordingly, before images and characters are recorded on the label surface of the recording disc, it may be necessary to provide a pit sequence on the label surface using the optical pickup.